Case-control studyindependent cross-checkabstract checked I-ABX-126 standard review
UK study: antibiotics not linked to breast cancer
Use of antibiotics and risk of breast cancer.
Overview
García Rodríguez LA et al.. Am J Epidemiol 2005 · PMID 15781950 · DOI 10.1093/aje/kwi087
A UK replication found no rise in breast cancer with antibiotic use.
Does the study support the specific claim? No · Methodological quality: moderate
Plain-language summary
Study explained simply
- What did the researchers want to find out?
Replicate the antibiotic-breast cancer link
- How was the study done?
Nested case-control
- How many people, animals or samples were studied?
3708 cases
- What was actually found?
No association
- How large was the observed effect?
OR 1.0 to 1.2 (all CIs include 1)
- What do the results mean in everyday life?
No sign of risk
- What are the study's limitations?
Observational
- What does it say about Elawady's specific claim?
Contradicts the claim
- Do the results apply to Germany and Europe?
High
- What can explicitly not be concluded from this study?
Not applicable
Scientific in-depth review
1. Full reference
- Authors
- García Rodríguez LA et al.
- Journal
- Am J Epidemiol
- Year
- 2005
- Identifier
- PMID 15781950 DOI 10.1093/aje/kwi087
- Verification
- verified – PubMed efetch 2026-10-26 + Crossref
- Retracted
- no
- Corrections
- none
- Extent checked
- abstract only
- Conflicts of interest and funding
Not stated in abstract.
2. Research question
Can the association between antibiotic use and breast cancer be replicated?
3. Study design and population
- Study design
- Case-control study – Nested case-control study (UK GPRD)
- Population
Women aged 30-79 in UK primary care
- Country
UK
- Period
1995-2001
- Sample size
3708 cases, 20,000 controls
- Inclusion and exclusion criteria
Registered women
4. Methods and endpoints
- Exposure / intervention
Cumulative days of antibiotic use
- Comparator
Non-use
- Endpoints
Incident breast cancer
- Statistical methods
Conditional logistic regression
5. Actual results
- Results
No increased risk: ORs 1.0 (0.9-1.1), 1.0 (0.8-1.1), 0.9 (0.7-1.0) and 1.2 (0.9-1.6) for 1-50, 51-100, 101-500 and >=501 days (p trend 0.31).
- Absolute risks
not reported
- Authors' conclusion
Antibiotic use does not appear to be a major determinant of breast cancer risk.
6. Strengths
- Replication design
- Prospectively recorded prescriptions
7. Weaknesses
- Observational
8. Risk of bias
- Orienting tool
- ROBINS-E
- Type of assessment
- simplified assessment (abstract only)
- Full formal assessment
- no
- Overall risk of bias
- low
- Rationale
Well-designed replication.
9. Assessment of the statistical interpretation
Null across exposure categories.
10. Relevance to the specific claim
Direct replication of Velicer's design failed to find an association.
11. Independent contrary findings
None major.
12. Transferability to Germany and Europe
High (UK).
13. Overall methodological judgement
Contradicts a consistent association.
| Multidimensional assessment | |
|---|---|
| Authenticity of the source | verified |
| Methodological quality | moderate |
| Risk of bias | low |
| Precision of results | moderate |
| Directness | direct |
| Reproducibility | partly replicated |
| Consistency with the overall evidence | inconsistent |
| Regional transferability | high |
| Adequacy of the interpretation (by the archive) | not applicable |
14. Open questions
None.
15. Linked fact checks
- Antibiotic use is associated with breast cancer (archive bibliography). – Studies contradicting or limiting the claim